Trojan Horse tactic may fool HIV

Tuesday, 7 November 2006 Maggie FoxReuters

Scientists hope they have a new way of tackling HIV/AIDS a bit like a Trojan Horse. They've engineered a 'faulty' version of HIV, infused it into the body and watched as it replicated harmless versions of itself (Image: iStockphoto)

"The virus is gutted so that it only has half the size of the original or pathogenic virus," June says.

Antisense approach

The so-called envelope gene remains, and is reversed, a manipulation called antisense.

The researchers then recruited five patients with HIV who were beginning to fail treatment. Their drugs no longer worked and the virus was beginning to damage their immune systems.

June's team removed the immune cells, CD4 T-cells, that HIV attacks. The researchers infected the CD4 cells in the lab with their newly engineered antisense HIV virus, then infused them back onto the patients.

When HIV or any other virus infects a cell, it injects its own genetic material into the cell. The cell is turned into a virus factory, sometimes pumping out thousands of copies of a virus before it explodes.

After the new antisense virus was infused, newly infected cells pumped out defective virus, June says.

"The virus particles that are released are, like, sterile. They are nonpathogenic," June says.

Safety first

This test was meant only to show that the approach was safe, and three years later, none of the patients show ill effects.

The treatment appears to have helped restore the immune systems of four of the five patients, and the virus remains partly suppressed.

"We put back more [CD4 cells] than we took out. We don't know if that is why their immune system gets better, because there are more soldiers, or whether it got better because of better antiviral effects," June says.

Phase II trials are under way in HIV patients who have disease well-controlled by drugs. June says it is not yet clear if the treatment could work only in infected patients, or might even be used as a preventive vaccine some day.